1. Field of the Invention
The present invention generally relates to an error recovery method for a disk, in particular, to an error recovery method for video recording.
2. Description of Related Art
Along with the coming of the information era and the increasing quantity of digital data of various sources and formats, optical storage media with large storage capacity, fast access speed, high portability, and easy storage has become one of the most indispensable tools.
Digital versatile disk (DVD) is a new generation optical storage medium. Both data density and capacity of a DVD are much higher than those of a conventional compact disk (CD). The formats of DVDs can be categorized into DVD-ROM, DVD-R, DVD-RW, DVD-RAM, DVD+R, DVD+RW etc. according to the applications and manufacturers thereof. A user can record video data or information data into a DVD conveniently by using a DVD video recorder or DVD recording device installed in a computer system.
However, a video recording process may fail due to bad quality of the disk, defects on the disk caused by improper usage (for example, scratches and fingerprints etc), or unexpected power failure during the recording process. In this case, the video data that were recorded onto the disk before the problem occurs becomes inaccessible.
To be specific, the processing of a file system on a disk during realtime video recording is different from that in a data burning software. The initial address of the file system is fixed when disk is being initialized; during the recording process before disk is being finalized, the address for the updated file system should be determined by the address of the last video data which is written onto the disk. If additional video is to be recorded onto the disk, a data detection operation is performed beforehand in order to obtain the up-to-dated file system, and the video can then be recorded onto the disk or the disk can be finalized based on the information from the latest file system.
FIG. 1 is a diagram illustrating the data in a conventional write-once DVD. Referring to FIG. 1, during the video recording sessions with a write-once DVD, a file system (file system 130 or 140) will be established each time at the end of the record session. The updated file system will locate right after the end address of a data segment (data segment 110 or 120) which contains the updated and descriptive information of the data segments on the disk, so that later on the data segments can be read and played-back by a player.
FIG. 2 is a diagram illustrating the data allocation on a conventional rewritable DVD. Referring to FIG. 2, during the video recording sessions with the rewritable DVD, file system 200 will be saved on a fixed section on the disk. It would be updated each time after a data segment (data segment 210, 220, or 230) is being recorded, so that later on the data segment can be read and play-back by a player.
However, when video is being recorded onto a disk, the duration of the video recording is usually determined by the user. Accordingly, the length and number of video data segments recorded onto a disk can not be known before the recording session ends. Thereby, once an error occurs during a video recording session, the session will be interrupted abnormally and the file system on the disk will fail to be updated in time. As a result, the disk will not be able to be used for further recording and even the previous recorded video sessions will be lost.